The present invention relates to an image-pickup apparatus including an image-pickup device, a method of fabricating the image-pickup apparatus, and a camera system using the image-pickup apparatus.
In general, image-pickup devices used for image-pickup apparatuses are fabricated by forming image-pickup elements on a semiconductor wafer by semiconductor fabrication processes, and cut the semiconductor wafer into chips. The image-pickup device thus obtained has a flat-plate shape having a large thickness as a whole, and thereby it exhibits a rigid, non-deformable shape characteristic. Further, an image-pickup plane formed on a principal plane of the image-pickup device is planar along the principal plane.
On the other hand, an object is imaged on an image-pickup plane of an image-pickup device through imaging lenses built in an imaging optical system.
FIG. 17 is a schematic side view showing a state in which an image-pickup device is arranged in combination with an imaging optical system. Referring to FIG. 17, a diaphragm portion 51A is integrally formed at the leading end of a lens barrel 51, and two imaging lenses 52A and 52B and an intermediate diaphragm 51B are built in the lens barrel 51. An image-pickup device 53 is arranged relative to the imaging optical system having the above configuration, with the central portion of the image-pickup device 53 aligned to the optical axis (optical center) of the imaging optical system.
In the case of imaging an object through imaging lenses, there generally occurs a lens aberration called xe2x80x9ccurvature of fieldxe2x80x9d. As shown in FIG. 18, if a focal point is adjusted to P1 at a central portion of the image-pickup device 53, the focal point becomes P2 at a peripheral portion of the image-pickup device 53 by the effect of the above-described curvature of field, to cause a deviation in focal point between the central portion and the peripheral portion of the image-pickup device 53. As a result, there occurs degradation of image-pickup characteristics such as unevenness in image quality between the central portion and the peripheral portion of the image-pickup device 53.
To cope with such an inconvenience, in the case of an imaging optical system having a large number of lenses, a lens aberration occurring in the imaging optical system has been corrected by suitable combination of these lenses, and in the case of an imaging optical system having a small number of lenses, a lens aberration has been corrected by adopting an aspherical lens.
The correction of a lens aberration by an imaging optical system, however, puts a large load on the design of the imaging optical system including lenses, and since the load on the design of the imaging optical system becomes larger with an increase in corrected amount of a lens aberration, the production tolerance of each lens becomes correspondingly stricter. Further, if the amount to be corrected of a lens aberration becomes larger to some extent, there is a possibility that the lens aberration cannot be sufficiently corrected, to thereby cause degradation of image quality.
An object of the present invention is to provide an image-pickup apparatus allowed to suitably cope with a lens aberration occurring in an imaging optical system, a method of fabricating the image-pickup apparatus, and a camera system using the image-pickup apparatus.
To achieve the above object, according to a first aspect of the present invention, there is provided an image-pickup apparatus including: an image-pickup device having a flexible shape characteristic; and a retaining member for retaining the image-pickup device in a specific shape.
According to a second aspect of the present invention, there is provided a camera system using an image-pickup apparatus, the image-pickup apparatus including: an image-pickup device having a flexible shape characteristic; and a retaining member for retaining the image-pickup device in a specific shape.
According to a third aspect of the present invention, there is provided a method of fabricating an image-pickup apparatus including an image-pickup device having a flexible shape characteristic and a retaining member for retaining the image-pickup device in a specific shape, the method including the step of: making the retaining member retain the image-pickup device in a specific shape by disposing the image-pickup device on the retaining member, and in such a state, blowing air to the image-pickup device from an image-pickup plane side of the image-pickup device or sucking air from the opposed side to the image-pickup plane through the retaining member.
With these configurations of the image-pickup device, the fabrication method thereof, and the camera system using the image-pickup apparatus, since the image-pickup device having a flexible shape characteristic is retained by the retaining member, when the image-pickup device is used in combination with an imaging optical system, a lens aberration occurring in the imaging optical system can be suitably corrected by making the retaining member retain the image-pickup device in a state in which the image-pickup device is curved in the thickness direction.